He told a forensic psychiatrist that he had always been fascinated by weapons and that he had only planted the device for a prank.

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An artist's impression of Smith appearing at the Old Bailey in LondonCredit: SWNS:South West News Service

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Smith had been inspired by ISIS, a jury at the Old Bailey heardCredit: Facebook

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The 20-year-old was on his way to a university lecture when he left the rucksack on a Jubilee Line tubeCredit: Central News

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Damon Smith has been found guilty of planting a bomb on a Tube trainCredit: Central News

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Prosecutors allege that Smith had more bomb-making equipment at his home in Rotherhithe, South East LondonCredit: SWNS:South West News Service

The court heard Smith made his first replica pipe bomb aged 14 after reading the Anarchist's Cook Book online.

He is a judo black belt as well as an avid poker player who won £500 on an online game the morning he planted the bomb.

Dr Ian Cummings said in a report: "He recalled watching the Boston Bombings and downloading the Al Qaeda magazine Inspire and visited some Islamic websites.

"He said at the time he didn't think it was an issue - he thought it was just an interest."

How altar boy became bomb obsessed teen

Jurors were told that Smith first became interested in bomb-making when he was 10 as "something to do when he was bored".
At the age of 12, he got a police baton and nunchucks from the US.
Jurors saw pictures and video of Smith posing with his collection, including a blank-firing self-loading pistol, a BB gun, knuckleduster and a knife.
He had also looked up details of the Boston Marathon bombing, the 1999 London nail bomber and other atrocities around the world.
In 2013, Smith was briefly a member of Urban Self Protection in Newton Abbott, a club run by a police officer to teach youngsters skills to defend themselves on the streets.
The officer found Smith "over-enthusiastic but well-behaved" and said he asked a lot of questions about what weapons he could carry legally.

Richard Carey-Hughes QC, for Smith, described him as a "white boy from Devon" and "tied to his mother's apron strings".

But prosecutor Jonathan Rees QC told jurors: "It may be you conclude the motivation for his actions are rooted in the fact of his interest in building an IED and his interest in events where an IED had been used in the past.

"He wanted to set it off in a public place where others had done before him.

"This fixation and lack of empathy allayed any concern he may have had for the consequences."

He was not charged with any terror offences, after the Crown Prosecution Service decided they couldn't prove he was radicalised.

For more on this story

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